A conventional vehicle door control system controls the lock and unlock conditions of individual doors based on a result of checking an ID code by bidirectional communications between a portable electronic key (portable device) and a vehicle electronic control unit mounted on a vehicle. In this system, proper communication areas are set inside and outside the vehicle. A request signal is transmitted in a fixed interval from transmitters in the vehicle unit. In this way, the system monitors that the holder of the portable device approaches, rides in and gets off the vehicle.
For example, when the holder of the portable device approaches the vehicle to ride in the vehicle and enters a communication area, in response to the request signal, the portable device returns a response signal including its ID code to the vehicle unit. When it is determined that a required relation is satisfied, that is, when the ID code acquired from the portable device coincides with a registered ID code in the vehicle unit, the vehicle unit sends a control signal to a door lock control device of the vehicle to drive individual doors into an unlock standby state. When the holder of the portable device touches a door handle in this state, the door lock control device detects it by a touch sensor or the like, and unlocks the door.
When the holder of the portable device gets off the vehicle after stopping a vehicle engine, the area of communication with the portable device shifts from the interior of the vehicle to the exterior of the vehicle. In this case, when a door switch provided near a door handle is operated, the door is locked.
According to the above system, the holder of the portable device can lock and unlock the doors without holding the portable device in hand, providing increased usability to the holder of the portable device.
Recently, an increasing number of vehicles have slide doors and rear doors equipped with an automatic opening/closing device that automatically opens and closes the doors by using an electric motor or the like as a power source. Some of such vehicles also include the above vehicle door control system. However, the automatic opening/closing device and the vehicle door control system operate independently from each other.
Specifically, the automatic opening/closing device is ordinarily actuated by operating an opening/closing switch provided in the portable device, or operates to automatically open the doors after the doors are unlocked, and then opened by a required degree of opening. The above vehicle door control system, locks and unlocks the doors through intercommunications between the portable device and the vehicle unit. Thus, the automatic opening/closing device and the vehicle door control system operate independently from each other although they control the same vehicle doors.